It is known in the art to utilize fencing to confine livestock in a defined area. Various types of fencing are available including wood, wire, barbed wire, chain link, and polymer fencing. In comparison to other types of fencing, polymer fencing provides significant advantages in terms of cost, aesthetics, visibility, and reduced risk of harm to any confined animals.
Numerous prior art polymer fencing systems are known. For example, U.S. Pat. No. 4,374,798 to Mercer discloses a plastic mesh structure suitable for use as fencing. Another particularly preferred polymer fencing system is disclosed in U.S. Pat. No. 4,465,263 to Robbins, Jr. (now U.S. Pat. No. Re. 32,707), comprising an elongated vinyl plastic webbing having parallel strands of high tensile wire encased therein. This latter fencing is designed to imitate wood fencing in terms of aesthetics while advantageously reducing the cost of purchase and maintenance associated with wood fencing. Both U.S. Pat. Nos. 4,374,798 and 4,465,263 are incorporated herein by reference.
In order for the fencing system to be effective regardless of the type of polymer fencing utilized, it must be placed under sufficient tension to prevent sagging of individual fencing members or strands. Standard tensioning devices for wire or barbed wire-type fencing are highly effective for their intended purpose. However, they suffer from the limitation that only a single strand of wire can be tensioned at a time. Accordingly, single wire prior art tensioning devices are unsuited for tensioning polymer fencing systems which either have a plurality of wires or within which individual wires cannot be accessed. This prior art tensioning device is particularly unsuited for applying tension to fencing systems that must be tensioned concurrently along two parallel edges.
Prior art systems for tensioning polymer fencing are known. For example, the tensioning system disclosed in U.S. Pat. No. 5,409,196 to Specht includes a mounting batten designed to be fastened to a structural support post. The mounting batten forces the polymer fencing against a correspondingly formed elastic extrusion or metal form channel batten, thereby placing the fencing under tension. Similarly, U.S. Pat. No. 5,660,377 to Specht discloses a tensioner bar designed to be fastened to a structural support post containing a correspondingly shaped recess. The tensioner bar forces the polymer fencing into the correspondingly shaped recess, thereby placing the fencing under tension. These systems are generally effective for certain types of polymer fencing. However, they suffer from the disadvantages of requiring either a specially formed structural support post or multiple components, such as mounting battens and correspondingly shaped channel battens. Accordingly, there is need in the art for a tensioning system for a polymer fence member which can be used with a standard, unmodified support structure such as a fence post.